We currently have low interest rates. This is a given. There is a 100% certainty of current rates against a much lower chance of them going up or down.
They MAY go lower. They MAY go higher. But ultimately interest rates can't go much lower, so savings are not going to be huge if they do reduce. The last Bank of England advice was that all mortgage owners should be able to cope with a rate increase of up to 3%. Which suggests that their worse case plans at the moment do not include the massive rises of the 1990s, but could include rises. The indications are that they will go down - BUT banks are not inclined to follow the BoE lead and I would suggest that at present, if banks are expected to be protected against crashes, then rates are less likely to go down as they need the money.
I don't think its about whether you are a gambler though. Its about what you can afford. And what you can't afford. Its about planning short term and long term. Not necessarily just for your mortgage.
I would also say to be mindful of what your future plans are. Are you likely to move within the term of your mortgage? How secure is your employment? (is there any chance you would be forced to relocate if you lost your job).
I would say if you have a fixed rate, I'd be conscious of when it finished as crap knows whats going to happen then politically due to the current Brexit timetable - and to plan for possibly getting stung by hikes then too. Build up a buffer against the possibility if you can.
If you are eligible for a offset mortgage and can afford to save, even a small amount, it is worth looking at. It gives you a better option than a normal savings account, by getting the interest against your mortgage (thus giving you more due to the effects of compound interest) or if interest rates do go up, would benefit from a increase.